Desorption of Potassium and Magnesium by Gray Forest Soil

It has been shown that a long-term potassium deficiency in the agrocenosis reduces the ability of gray forest soil to desorb this element into the soil solution to a much greater extent than magnesium deficiency – magnesium desorption. It has been established that the mobility of potassium cations is greater than that of magnesium, regardless of the degree of soil depletion in relation to these elements: 0.1–0.5 M ammonium acetate solution extracted almost the entire soil stock of exchangeable potassium, whereas magnesium – only 65–90%. During fractional extraction of potassium with 0.001 M ammonium acetate solution, differences between soils with different potash content were noted only in the first 2–3 extracts; in the following extracts, the potassium content was equalized. The magnesium content in successive extracts decreased gradually and approximately equally in soils with its different initial content. It has been shown that the intensity and specificity of soil desorption of potassium and magnesium well reflects soil fertility in relation to these elements.